TY - JOUR
T1 - Membrane dipole potential is sensitive to cholesterol stereospecificity
T2 - Implications for receptor function
AU - Bandari, Suman
AU - Chakraborty, Hirak
AU - Covey, Douglas F.
AU - Chattopadhyay, Amitabha
N1 - Publisher Copyright:
© 2014 Elsevier Ireland Ltd. All rights reserved.
PY - 2014/12
Y1 - 2014/12
N2 - Dipole potential is the potential difference within the membrane bilayer, which originates due to the nonrandom arrangement of lipid dipoles and water molecules at the membrane interface. Cholesterol, an essential lipid in higher eukaryotic membranes, has previously been shown to increase membrane dipole potential. In this work, we explored the effect of stereoisomers of cholesterol, ent-cholesterol and epi-cholesterol, on membrane dipole potential, monitored by the dual wavelength ratiometric approach utilizing the probe di-8-ANEPPS. Our results show that cholesterol and ent-cholesterol share comparable ability in increasing membrane dipole potential. In contrast, epi-cholesterol displays a slight reduction in membrane dipole potential. Our results constitute the first report on the effect of stereoisomers of cholesterol on membrane dipole potential, and imply that an extremely subtle change in sterol structure can significantly alter the dipolar field at the membrane interface. These results assume relevance in the context of differential abilities of these stereoisomers of cholesterol in supporting the activity of the serotonin1A receptor, a representative G protein-coupled receptor. The close correlation between membrane dipole potential and receptor activity provides new insight in receptor-cholesterol interaction in terms of stereospecificity. We envision that membrane dipole potential could prove to be a sensitive indicator of lipid-protein interactions in biological membranes.
AB - Dipole potential is the potential difference within the membrane bilayer, which originates due to the nonrandom arrangement of lipid dipoles and water molecules at the membrane interface. Cholesterol, an essential lipid in higher eukaryotic membranes, has previously been shown to increase membrane dipole potential. In this work, we explored the effect of stereoisomers of cholesterol, ent-cholesterol and epi-cholesterol, on membrane dipole potential, monitored by the dual wavelength ratiometric approach utilizing the probe di-8-ANEPPS. Our results show that cholesterol and ent-cholesterol share comparable ability in increasing membrane dipole potential. In contrast, epi-cholesterol displays a slight reduction in membrane dipole potential. Our results constitute the first report on the effect of stereoisomers of cholesterol on membrane dipole potential, and imply that an extremely subtle change in sterol structure can significantly alter the dipolar field at the membrane interface. These results assume relevance in the context of differential abilities of these stereoisomers of cholesterol in supporting the activity of the serotonin1A receptor, a representative G protein-coupled receptor. The close correlation between membrane dipole potential and receptor activity provides new insight in receptor-cholesterol interaction in terms of stereospecificity. We envision that membrane dipole potential could prove to be a sensitive indicator of lipid-protein interactions in biological membranes.
KW - Cholesterol
KW - Dipole potential
KW - Ent-cholesterol
KW - Epi-cholesterol
KW - Serotonin receptor
KW - di-8-ANEPPS
UR - http://www.scopus.com/inward/record.url?scp=84908463318&partnerID=8YFLogxK
U2 - 10.1016/j.chemphyslip.2014.09.001
DO - 10.1016/j.chemphyslip.2014.09.001
M3 - Article
C2 - 25219773
AN - SCOPUS:84908463318
SN - 0009-3084
VL - 184
SP - 25
EP - 29
JO - Chemistry and Physics of Lipids
JF - Chemistry and Physics of Lipids
ER -